1. Field of the Invention
This disclosure relates to the generation of ultrasound signals and, more particularly, to an ultrasonic controller for use with an ultrasonic transducer to accelerate the process of healing in both hard and soft tissue.
2. Description of the Related Art
The therapeutic value of ultrasonic waves is known. Various techniques and devices are used to apply ultrasound waves to various areas of the body. In one known technique a pulsed radio-frequency ultrasonic signal applied via a transducer to the skin of a patient and is directed to the site of the wound. The radio-frequency signal is in the range of 1.3 to 2 MHZ, and it consists of pulses at a repetition rate of 100 to 1000 Hz, with each pulse having a duration in the range of 10 to 20,000 microseconds. See, e.g. U.S. Pat. No. 4,530,360 to Duarte and U.S. Pat. No. 5,520,612 to Winder et al.
U.S. Pat. Nos. 5,003,965 and 5,186,162 both to Talish and Lifshey ("Talish '965" and "Talish '162", respectively) describe an ultrasonic delivery system where the R-F generator and transducer are both part of a modular applicator unit that is placed at the skin location. The signals controlling the duration of ultrasonic pulses and the pulse repetition frequency are generated apart from the applicator unit. Talish '965 and Talish '162 also describe fixture apparatus for attaching the applicator unit so that the operative surface is adjacent the skin location. In Talish '965 and Talish '162, the skin is surrounded by a cast, while in U.S. Pat. No. 5,211,160 to Talish and Lifshey ("Talish '160") fixture apparatus is described for mounting on uncovered body parts (i.e., without a cast or other medical wrapping). Talish '160 also describes various improvements to the applicator unit. Duarte, Talish '965, Talish '162 and Talish '160, are all incorporated into this application by reference.
As ultrasonic self-treatment becomes more popular, a need arises to make ultrasonic delivery systems easier and more convenient to use. Current ultrasonic transducers for home use create opportunities for the patient, participating in self-treatment, to make errors in time of exposure or improperly setting up the apparatus, for example, inadequate amounts of ultrasound coupling gel being used on the interface between the ultrasound transducer and the skin over the region where the defect exists. A daily 20 minute treatment session has been established as effective in accelerating healing of certain bone fractures. The effects of longer treatment are usually of no benefit to the patient. However patient compliance is necessary in order for the true benefits of ultrasound treatment to be realized. Therefore, self-treatment programs should be monitored and controlled.
Rigidly adhering to a 24 hour delay between treatment sessions often puts an unrealistic constraint on a patient with a self administrated treatment device. Non-routine occurrences or unexpected events often interfere forcing a patient to advance or delay treatment rather than skip the treatment session. A contiguous 20 minute session is preferred for each treatment with ultrasound, however, this period can be interrupted by common everyday events, for example, the door bell ringing. Therefore, a need exists for a treatment system that allows a patient to advance or delay treatment and which automatically prevents any unnecessary over treatment. There also exists a need to provide the flexibility to stop a treatment session and start up again within a reasonable time, with automatic protection against over treatment.
In order for a treatment session to be beneficial to a patient, at least a portion of the ultrasound wave must penetrate the body and reach the injury to accelerate the healing process. In order to minimize excessive attenuation of the ultrasound waves produced by the transducer, an ultrasonic wave coupling material, e.g. a conductive gel, is used between the surface of the skin and the transducer head. If an inadequate amount of gel is used or it is improperly applied by the patient to herself, the treatment session will not be as effective as it should be. Therefore, a need exists for determining whether or not a gel layer is properly applied or even if the patient forgets to apply the gel before treatment.
Ultrasonic treatment systems are made up of many components. Variations in component tolerances in the output driver circuitry or the output transducer, for example, create a need to perform minor adjustments to the output power level in order to achieve the required level of compliance. Although a manual tuning component traditionally works, its use requires a labor intensive process which can raise the cost of the final product. Therefore, a need to reliably set power levels and perform minor adjustments for ultrasonic transducers exists.
Patients often forget to keep and maintain accurate treatment logs. The duration of each treatment session and the time interval between treatments can prove to be important information for a treating physician or a patient. It would be advantageous to have a device that was capable of logging time efficiently and accurately to create a cumulative treatment history without relying on the patient to keep appropriate records.